A Car Alternator Explained (Briefly) and What It Does

Summary:

Have you always believed the battery powers all the electrical components in your car? While the battery provides power when the engine isn’t running and helps start the vehicle, an alternator does the rest. Components such as wipers, radios, and headlights receive power from the alternator instead of the battery. 

An alternator is a critical part of your car’s charging system. Hence, knowing what it is and how it works is beneficial. We’ll discuss how an alternator operates, the factors causing it to go wrong, and answer other frequently asked questions. 

What Does an Alternator Do?

An alternator converts mechanical energy into electricity used by various car components. The electricity generation begins with the engine, as the crankshaft drives alternators in most modern vehicles. However, if you have an old car, a separate pulley might run from the crankshaft to the alternator. 

An alternator generates electricity as its rotor spins. The rotor has magnets surrounding it, forming a magnetic field. The magnetic field then produces voltage stored by the stator, reaching the voltage regulator. The regulator then diverts the power to different electrical components in your car and determines how much voltage the battery should receive.

What Causes an Alternator to Go Bad?

Several factors can cause your car’s alternator to go bad. Some of these common reasons include the following. 

1. Dust and Dirt

Dust and dirt accumulating on the alternator can trigger issues. These can instigate shorts or wear on the brushes. However, avoid using a carb cleaner or gasoline to remove dust, as it can damage the thin insulation on wire windings, adversely affecting the magnetic field. 

2. Heat and Oil

Heat and oil exposure to the alternator can be damaging, and it tends to shorten the alternator’s life. Frequently inspect under the hood to notice any leaks and tackle them immediately. 

3. Faulty Components

An alternator consists of different components and issues with any of them can cause it to fail. Examples include worn-out wires, problems with the ECM computer system, bad fuse, and broken pullet or belt. Problems with any of these parts can affect the power transfer to your car’s electrical components.

Bad Car Battery or Faulty Alternator? Know the Signs

When diagnosing issues with a vehicle’s electrical system, it’s crucial to distinguish between signs of a failing car battery and a malfunctioning alternator. Here’s a breakdown to help identify which component might be causing trouble:

Signs of a Bad Car Battery

• Difficulty Starting the Car: The engine cranks slowly, or you hear a clicking noise without the engine starting.
• Age: Car batteries typically last 3-5 years. If yours is older, it might be time for a replacement.
• Dim Lights and Electrical Issues: Dimming headlights and dashboard lights or malfunctioning electronic accessories can indicate a battery struggling to maintain charge.
• Visible Corrosion: White, ashy substance on the metal parts of the battery or corroded terminals can lead to poor connections.
• Swollen Battery Case: A battery case that appears bloated or swollen is a sign of excessive heat exposure, leading to a decreased battery life.

Signs of a Bad Alternator

• Battery Warning Light: The battery light or check engine light on the dashboard comes on, indicating potential alternator issues.
• Dead Battery: The alternator fails to charge the battery, leading to a dead battery when the car has been running.
• Dim or Overly Bright Lights: Flickering or excessively bright lights while driving can indicate an alternator failing to regulate power output properly.
• Strange Noises: Squealing or growling noises can result from a failing alternator bearing or misaligned pulleys.
• Electrical Failures: Alternator issues can cause erratic electrical operation, such as sudden loss of power to accessories or unexpected stalling.

Can you jumpstart a car with a bad alternator?

Yes, you can jumpstart a car with a bad alternator, but it’s a temporary solution. Jump-starting can get the engine running, but since the alternator is responsible for charging the battery while the engine operates, the car might not run for long after the jump. It’s crucial to address the alternator issue promptly to avoid further damage or getting stranded. For detailed steps and precautions, consulting a professional mechanic is recommended.

Can an Alternator Drain a Battery & How Much Money is a New One?

Among the different functions of an alternator is battery recharging. However, a bad alternator can also drain the battery. A faulty alternator fails to transfer enough power, eventually draining the battery. Therefore, next time your battery dies, we advise you to check the alternator for any faults before replacing the battery. 

Related – How To Change a Car Battery Yourself (And How Long They Last)

The alternator prices vary according to your car’s brand, size, and amp requirements. Generally, an alternator costs around $130 to $300 or more. However, also consider the mechanic’s charge for installing the alternator. Furthermore, if your bad alternator has drained your battery, you must worry about replacing it.  

Takeaway

While the battery helps start the vehicle, it does not power all the electrical components in the car. An alternator, part of the car’s charging system, produces electricity for wipers, radio, headlights, and other components.

It’s made of different parts, such as rotors that spin to produce electricity and transfer it to the voltage regulator, diverting power to the rest of the car. However, dust, dirt, heat, and oil can damage the alternator and drain your battery. A failed alternator would require a replacement, costing about $130 to $300, excluding the mechanic’s installation charge.